Apparatus for Regulator with Improved Performance and Associated Methods

Abstract

An apparatus includes an integrated circuit (IC), which includes a voltage regulator. The voltage regulator includes a first transistor coupled to an input voltage of the voltage regulator and a first output of the voltage regulator. The first transistor includes a native device of the IC. The voltage regulator further includes at least one diode-connected transistor coupled to the first output of the voltage regulator.

1 . An apparatus comprising:
 an integrated circuit (IC) comprising:
 a voltage regulator comprising:
 a first transistor coupled to an input voltage of the voltage regulator and to a first output of the voltage regulator, wherein the first transistor comprises a native device of the IC; and 
 at least one diode-connected transistor coupled to the first output of the voltage regulator. 
 
   
     
     
         2 . The apparatus according to  claim 1 , wherein the voltage regulator comprises a resistor coupled in series with the at least one diode-connected transistor. 
     
     
         3 . The apparatus according to  claim 2 , further comprising:
 a second transistor coupled to the input voltage of the voltage regulator, to the bias circuit, and to a second output of the voltage regulator, wherein the second transistor comprises a native device of the IC; and   a pair of diode-connected transistors coupled to the second output of the voltage regulator.   
     
     
         4 . (canceled) 
     
     
         5 . (canceled) 
     
     
         6 . The apparatus according to  claim 1 , further comprising a first capacitor coupled to a gate of the first transistor. 
     
     
         7 . The apparatus according to  claim 6 , wherein the first capacitor provides a dominant pole of a transfer function of a negative feedback loop of the voltage regulator. 
     
     
         8 . The apparatus according to  claim 6 , wherein the transfer function of the negative feedback loop of the voltage regulator further comprises a pole corresponding to a capacitor coupled to the first output of the voltage regulator, wherein the pole has a frequency that is larger than 2.2 times a frequency of the dominant pole. 
     
     
         9 . The apparatus according to  claim 2 , wherein a length of one of the two diode-connected transistors is selected in order to trim the output voltage of the voltage regulator. 
     
     
         10 . An apparatus comprising:
 a microcontroller unit (MCU), integrated as an integrated circuit (IC), comprising:
 a voltage regulator comprising:
 a first transistor coupled to an input voltage of the voltage regulator and to a first output of the voltage regulator, wherein the first transistor comprises a native device of the IC; 
 first and second diode-connected transistors coupled to the first output of the voltage regulator; and 
 a bias circuit comprising a current source coupled to a second transistor, the bias circuit providing a bias voltage to the first transistor and to the first diode-connected transistor. 
 
   
     
     
         11 . The apparatus according to  claim 10 , further comprising a first capacitor coupled to a gate of the first transistor and to the current source. 
     
     
         12 . The apparatus according to  claim 10 , further comprising:
 a first resistor coupled in series with the first and second diode-connected transistors; and   a second resistor coupled in series with the second transistor.   
     
     
         13 . The apparatus according to  claim 10 , wherein the first diode-connected transistor forms a current mirror with the second transistor. 
     
     
         14 . The apparatus according to  claim 10 , further comprising:
 a third transistor coupled to the input voltage of the voltage regulator, to the bias circuit, and to a second output of the voltage regulator, wherein the third transistor comprises a native device of the IC; and   third and fourth diode-connected transistors coupled to the second output of the voltage regulator.   
     
     
         15 . A method of regulating an input voltage, by using a voltage regulator integrated in an integrated circuit (IC), the method comprising:
 regulating the input voltage via a first transistor coupled to receive the input voltage and to provide a first regulated output voltage at a first output of the voltage regulator, wherein the first transistor comprises a native device of the IC; and   using at least one diode-connected transistor to couple the first output to a ground potential.   
     
     
         16 . The method according to  claim 15 , further comprising:
 regulating the input voltage via a second transistor coupled to receive the input voltage and coupled to a second output of the voltage regulator to provide the second regulated output voltage, wherein the second transistor comprises a native device of the IC; and   using one or more diode-connected transistors to couple the second output to a ground potential.   
     
     
         17 . The method according to  claim 15 , further comprising using a first capacitor to provide a dominant pole of a transfer function of a negative feedback loop of the voltage regulator. 
     
     
         18 . The method according to  claim 17 , further comprising using a second capacitor coupled to the first output of the voltage regulator to provide a pole corresponding to the second capacitor, wherein the pole has a frequency that is larger than 2.2 times a frequency of the dominant pole. 
     
     
         19 . The method according to  claim 15 , wherein using at least one diode-connected transistor to couple the first output to the ground potential comprises using two diode-connected transistors. 
     
     
         20 . (canceled) 
     
     
         21 . The method according to  claim 17 , wherein the transfer function of the negative feedback loop of the voltage regulator further comprises a pole corresponding to a capacitor coupled to the first output of the voltage regulator, wherein the pole has a frequency that is larger than 2.2 times a frequency of the dominant pole. 
     
     
         22 . The method according to  claim 15 , wherein using one or more diode-connected transistors to couple the second output to a ground potential further comprises using a resistor coupled in series with the one or more diode-connected transistors. 
     
     
         23 . The method according to  claim 22 , wherein a length of one of the two diode-connected transistors is selected in order to trim the output voltage of the voltage regulator.